This invention relates to printers that require some tangible time between a nonprinting status and actual marking on paper or other sheets. More specifically, this invention relates to improving the time to begin printing of the first sheet of a job, depending on the mode of the printer immediately before such printing.
In laser printers of today, time to first print is often limited to the printhead lock time, which has been specified as a single time for all printing modes. Different printing modes in this context include off as one mode and on but inactive (standby), as another mode. Printhead lock is simply the stable operation of the laser printhead at a predetermined speed, and printhead lock time is the time from start from inactive or partially inactive to printhead lock.
The printhead lock time for all printing modes necessarily assumes operating conditions at minimum voltage and minimum temperature over the life of the printer. This results in a specified lock time that is significantly longer than typical operation. However, if this lock time were reduced for all printing, the number of printing failures would increase.
In accordance with this invention, the lock time is left at a conservative, longer amount for one mode of the printer and is set at a shorter time for another mode of the printer. Additionally, when the lock time is the shorter lock time, recognition of a print failure or potential print failure related to the shorter time is responded to by lengthening the lock time for all subsequent printing.
In the embodiment disclosed, the lock time is the assumed time from slow or off of the polygon mirror of a laser printer to stable rotation of the polygon mirror. The mode from which the longer amount is employed is printing after the printer full off. The longer time is selected because at full off the printer may be unusually cold or otherwise not stabilized to its environment. The other mode is printing from standby or another power-on state. At standby, the motors and heaters of the printer typically have operated enough in the recent past to have stabilized the printer to its normal environment and the fuser is still being partially warmed to a level permitting quick printing. The motor rotating the polygon mirror is typically off at standby. The paper or other sheet to be printed is picked based on time from initiation of the print cycle. If the sheet reaches the print area at the expected lock time but the printhead has not locked, failure occurs, and all subsequent lock times are adjusted to the longer lock time.